Process of making phosphate fertilizer.



CHARLES R. mnnrwn'rnnn, or rnaiv'ron, KENrueKY.

I PROCESS OF MAKING PHOSPHATE FERTILIZER No Drawing.

Specification of Letters Patent.

Application. flled'April 18, 1912. Serial No. 691,771.

Patented Apr. 8, 1913.

To all whom it may concern:

Be it known that I, CHARLES N. MERL- WEIHER, a citizen of the United States, re siding at Trenton, in the county of Todd and State of Kentucky, have invented certain new and useful Improvements in Processes of Making Phosphate Fertilizer; and'I-do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to that class offertilizers made from mineralphosphate rock or bone black to render the phosphorus con-' tained therein readily available for plants.

The object of the invention is to provide a new method of breaking up the neutral salts in which the phosphorus is found by the use of other salts or bases mixed with the salts containing the phosphorus. The salts or bases employed have been used heretofore for the same purpose but I have discovered a new method of using'them whereby an improved result is produced and economy in manufacture effected. This improved method of liberating phosphorus from phosphate rock consists in mixing phosphate rock with lime rock and grinding them together, then putting the round resulting product into a furnace an heating it to a temperature 'of about 1000C.

- This ground material is then run out and combined with a compound of sodium or other salts, which will be hereinafter described, and reground, The reground material is then placed in the furnace and reheated to a temperature of about 800 C.

When it is desired to also combine a com-- pound ofpotassium with the mixture, the material is run out, reground with the compound of potassium, and then againrun out and ground, in which condition it 1s ready for use as-a fertilizer.

r The gist of this invention resides in adding the salts or bases which are to be mixed with the mineral phosphates to break up neutral salts, at diiferent times, as I have found thatone material added at different times has a much better effect, than if added all at once, for example, when one-half of the lime to be employed ,is added to the phosphate rock and the compound calcined, and then pulverized again with the other half of the lime to be used, and then recalmaterial for use as a fertilizer.

cined, a much better effect is produced than i if all the lime were added at one time.

When-potash or any compound of pot-assium is used, it may be added with the soda or any compound of sodium, or a large quantity thereof may be added as a substitute for the soda or any sodiumcompound.

I have found that when using rock containing sixty-five per cent. of bone phosphate lime, a desirable proportion consists .of'one hundred pounds of rock, seventy-five pounds of limestone, twenty poundsof sulfate of soda and ten pounds of sulfate of potash. I have also found that the addition of about five per cent. iron oxid, if the rock has not that element in it naturally, facilitates the transformation of the phosphorus hasbeen found that the larger the proportion of lime used the larger proportion of phosphorus is changed into available form, but for general pur oses the amount above stated is found desirable. When the fertilizer' is to be used on ,soil which requires 'lime, an excess of lime may be used in the produce the change in the availability of the phosphorus or plant food varies greatly, according to the other constituents of the rock, fluorin,.silica, alumina, etc., often 0on stituting from ten to fifty per cent. of the weight of the rock; neither can it be stated before trial whether it is .best to fuse'the rock from a given mine or to semi-fuse or calcine it. While fusion does not injure the product, it is not generally necessary to fuse the rock, andthus a cat saving in both the fuel used, and in t e wear of the furnace is effected.

Phosphatic limestone sometimes contains about the proper proportion of carbonate of lime and phosphate of lime, and this material is then calcined sufficiently to drive off the carbon dioxid, and this step consti- Also, it

tains natural carbonate of lime, the amount above must be changed according to the:

nature of the phosphate rock being treated and the quick or slow acting product which is wished to be obtained; If the rock conof limestone added must be reduced proportionately. i Q

In producing a fertilizer the compound of sodium and potassium may be added at the same time, and other compounds of sodium and potassium than those specified may be employed, also the order in which the various ingredients are added may be changed and the materials may be added at different times without removing the mass from the furnace and regrinding, without departing from the principle of this invention, which is that the cumulative effect of the materials added to effect the transformafionnspec'ified is greater when said materials are added at difierent times than when the same quantities of these materials are added simultaneously.

I claim as my invention:

1. A process of manufacturing phosphate fertilizer from mineral phosphates which consists in addin an alkali to the mineral phosphate'at di erent times and calcining said material between such additions.

2. The process of manufacturing hosphate fertilizer from mineral phosp ates which consists-in adding an alkali to the mineral phosphates, then calcining the resulting product, then addin more of the alkaline substance, then reca cining the resulting product, and finally pulverizing it.

3. 'lheprocess of manufacturing phosphate fertilizer from mineral phosphates which consists in calcining the phosphate, then adding an alkali, and then regrinding' and recalcining the resulting product.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses. f

CHARLES N. MERIWETHER.

Witnesses: v

R. A. GARDNER, MIGHL. J OSEZH. 

